how in the world did that thing come off? With 6 bolts holding it down it should have made a big mess when they got just a little loose (and smoked you engine)
to answer your original question, there is no timing to do. Just make sure the dot on both gears are on the same side. Personally i'd put a new pump in while you're there as they are really cheap.
The trick is setting the end play and keeping everything clean. There's plenty of people that have shotgunned pumps with the cover on the car but the only way to do it right is to pull the cover.